In the United States, there are approximately 4 million births per year and childbirth is the leading indication for hospitalization. Correspondingly, the prevention of adverse obstetric outcomes, including preterm birth and maternal morbidity, is an important goal, and clinical trials and observational studies designed to improve obstetric outcomes are of the utmost importance. The Maternal-Fetal Medicine Units (MFMU) Network, by creating a multi-institutional research infrastructure, is an important mechanism to accomplish this goal effectively. The Northwestern Study Center, through its use of innovative recruitment techniques and study design approaches, has been a productive member of the MFMU Network since 2001, and is composed of two institutions that have worked together in the MFMU Network for over 10 years: Northwestern University and NorthShore University Health System. The two Maternal-Fetal Medicine Divisions of the institutions, in addition, have a long and continuing collaboration on multiple other clinical research studies and trials. In this proposal, we present the application of the Northwestern Study Center to renew its participation in the MFMU Network. Led by a team of experienced clinical researchers (William Grobman, MD, MBA; Alan Peaceman, MD; Mara Dinsmoor, MD, MPH; Gail Mallett, RN), the Northwestern Study Center will continue its significant contributions to the MFMU Network's goals though robust enrollment of socioeconomically diverse patients and the conception and development of novel studies.